1. Field of the Invention
The present invention is related to computers and, more particularly, to input devices for portable computers.
2. Description of the Background
Continued advances in semiconductor technology are producing high performance microprocessors requiring less power and less space. Reductions in power and space have led to portable computers. Decades of research in computer science have provided the technology for hands-off computing using speech and gesturing for input. Miniature heads-up displays weighing less than a few ounces combined with mobile communication technology make it possible for users to access information from virtually anywhere. It is even possible to sense a user's position such that information can be superimposed upon the user's workspace.
Currently, wearable and other types of portable computers are all hampered by the need for the user to be able to input information or commands in an ergonomic and convenient manner. The use of a full sized keyboard cancels many of the benefits gained by having a small portable or wearable computer. The provision of the keyboard also assumes that the user of the computer, perhaps maintenance workers, are capable of using the keyboard in an efficient manner. A mouse input device overcomes the problems associated with a keyboard, but the use of the mouse becomes impractical in confined areas where there is no flat surface on which to operate the device. Trackballs alleviate that problem, but many people find such devices difficult to operate. Furthermore, the delicate mechanism of the trackball quickly becomes inoperative in the manufacturing or maintenance environment where workers' hands are often heavily soiled or gloved. Voice input is hampered by the difficulties inherent in enabling computers to understand the spoken word.
The development of mobile computers has been ongoing at Carnegie-Mellon University, the assignee of the present invention, from at least as early as 1991. A system known as VuMan 1 was conceived in 1991. That system allowed the user to maneuver through the blueprints of a house using three buttons for input, much like a mouse. Output was provided on a commercially available head-worn display which gave the illusion of viewing a personal computer screen from about five feet. A full discussion of the VuMan 1 can be found in Akella et al. "Concurrent Engineering: A Prototyping Case Study," Proceedings of the 3rd IEEE International Workshop on Rapid System Prototyping, Research Triangle Park, N.C., June 1992.
The next generation of the computer was referred to as VuMan 2. The VuMan 2 computer was built in 1992 for the purpose of allowing the user to navigate the Carnegie-Mellon University campus. The VuMan 2 computer had a database of buildings, departments, and people so that a user unfamiliar with the campus could find the location of an appointment, get information on a faculty member such as a phone number or office number, or locate a specific building on the campus. Like the VuMan 1 computer, the VuMan 2 computer used the same commercially available head-worn display and three buttons for input. The VuMan 2 computer, however, was not dedicated to a single application. New applications could be loaded via a flash memory card. A second application developed for the VuMan 2 computer was an electronic maintenance manual for an alternator. The user could scan through manual pages then access the corresponding diagram. Additional information about the VuMan 2 computer is found in Smailagic, et al., "A Case Study In Imbedded Systems Design: The VuMan 2 Wearable Computer," IEE Design and Test of Computers, Volume 10, No. 3, pages 56-67, September 1993.
The initial application of a third generation mobile computer, the Navigator 1 computer, built in 1993, was a campus navigational tool similar to the VuMan 2 computer. Unlike the VuMan 2 computer, the Navigator 1 computer could use speech as input, allowing completely hands-free operation. The Navigator 1 speech recognition system was speaker-independent and had a 200 word vocabulary. A mouse was also available in case the speech recognition rate was low or speaking was undesirable. Another major difference between the Navigator 1 computer and the VuMan 2 computer was that the Navigator 1 computer was a general purpose computer while the VuMan 2 computer was embedded. The Navigator 1 computer ran the Mach operating system, allowing applications to be developed on a Unix workstation and then transferred to the Navigator platform. Software developers could use the standard Unix environment, such as X Windows and Shell scripts, in their applications. A third difference is that the Navigator 1 computer's architecture was modular so that the hardware could be reconfigured based upon the application. Additional information can be found in Siewiorek et al., "An Interdisciplinary Concurrent Design Methodology as Applied to the Navigator Wearable Computer System," Journal of Computer and Software Engineering, Vol. 3, No. 2, 1994.
The next generation of mobile computer, known as the VuMan 3, incorporated a new housing designed to withstand shock, temperature, water, and dirt. This generation of mobile computer was used as a maintenance assistant, and is referred to as VuMan MA when used in that application. This generation used an input interface which is a combination of a rotary dial and a push button. The speed and ease for a user to scroll through many options that may appear on the screen are the reasons for the use of a rotary dial. Further information may be found in U.S. patent application Ser. No. 08/399,203 entitled Portable Computer System With Ergonomic Input Device filed Mar. 6, 1995, and assigned to the same assignee as the present invention.
The next generation in mobile computing at Carnegie Mellon University was the Navigator 2 computer which is a general purpose system directed toward multi-media applications. The speech recognition system, having a secondary, manually controllable cursor, offers complete control over the application in a hands-free manner, allowing the operator to perform equipment inspections with minimal interference from the wearable system. The position of the cursor is manually controlled through the use of a joy stick.
Despite advances, speech recognition is often not the best mode of input due to noise in the environment, regional variations in speech, etc. Furthermore, advances in manufacturing toward reducing the size of components cannot be fully realized due to the fact that the human hand must have an input device of a given size which can be manipulated or actuated in dirty environments, or environments where the hand is gloved. Thus, the need exists for a rugged, ergonomic, inexpensive input device that can be used with a portable computer system to allow the full benefits of the portable computer system to be realized.